The preparation, storage and service of such beverages as hot chocolate, coffee and tea or of such foods as bouillons and soups, present unique logistical problems which render most available vessels inadequate for the above-stated purposes. Such well known containers as the ubiquitous coffee pot, or urns of traditional design can be efficiently employed to heat and serve a pourable comestible. The most significant problems are encountered when the above-mentioned containers are used to maintain such products for prolonged periods of time. For example, coffee which is stored in traditional covered containers, oxidizes upon exposure to and interaction with the surrounding air. This interaction gives rise to off-flavors, rendering the product unacceptable to consumer tastes. Loss of aromatic and desirable volatiles from the exposed surface of the liquid is also a detrimental factor. As the void between the upper level of the comestible and any stationary cover increases, the potential for exposure to outside atmospheric contamination increases as does the potential for the loss of endogenous volatiles.
The problem of oxidation of and loss of volatiles from flowable foodstuffs which must be kept in a heated condition for extended periods of time is well-known in the art. In fact, there are several prior art references which disclose specific embodiments for enclosing a liquid foodstuff beneath a sealing member to prevent oxidation or contamination. U.S. Pat. No. 551,540 discloses such an appliance that has a floating lid which seals liquid within a container. U.S. Pat. No. 1,948,353 shows a similar article, as does U.S. Pat. No. 3,804,635.
U.S. Pat. No. 1,990,918 to Ramsden discloses a serving pitcher containing parallel walls and a float adapted to rest upon and substantially cover the liquid surface within the pitcher. The Ramsden float was taught to fit within the pitcher "sufficiently closely to exclude practically all the air" and was intended to prevent the formation of skin or scum on milk after heating or boiling. Ramsden also discloses the possibility of placing an aperture in the float to enable insertion of a stirring rod into the liquid.
U.S. Pat. No. 3,987,941 issued to Blessing, discloses a container for preserving liquids or other liquid food products wherein a cylindrical container is fitted with a follower lid which is supported by the upper level of the liquid and descends downward as the contents of the container are dispensed via a spigot located thereinbelow. This reference discloses a lid which adaptively employs a flexible seal, said seal being attached to the perimeter of the round lid so that an essentially air tight relationship relative to the liquid food product results. The lid is of a diameter which at least equals the inside diameter of the vessel in Blessings design. Moreover, the above-cited design must be incorporated into a non-pourable, static "urn-type" dispensing appliance. Under these design constraints the contents can never be poured from the container, for the lid would tumble out of the container. A spigot located along the bottom well of the tank is the sole egress means for removing the heated beverage from the reservoir. In fact, the lid is weighted so that its center of gravity is as low as possible and is located at the center point of the lid; it is designed so that its travel path is restricted to an upward and downward movement making it impossible to tilt the appliance and the lid to thereby effect pouring.
U.S. Pat. No. 3,974,758 to Stone discloses the use of a sealed or unsealed follower lid in a straight-walled, pour-type coffee maker. This patent further discloses the use of a coventional pour spout of relatively small cross-sectional area whereby coffee from the bottom of the coffee maker is poured from the spout or the use of a pour lip at the upper end of the coffee maker whereby coffee is removed from the top of the coffee maker.
Published European patent application No. 110,617 to Spotholz et al. discloses a floatingly retained, insulation lid which tracks the level of a beverage contained in a vessel and prevents oxidation, loss of volatiles, and contamination of said beverage.
It has been found that the prior art systems do not permit preparation of a homogeneous beverage of uniform consistency with a floating lid in place within a vessel.
It is an object of the present invention to provide a lid for use in a vessel which is employed to receive and dispense liquids, said lid permitting preparation of a homogeneous beverage of uniform consistency.
It is a further object that the lid prevent oxidation, loss of volatiles and contamination of the beverage contained in the vessel.